In advanced and complicated city spaces such as airports, business parks, shopping centers, resort facilities, etc., a safe means of transportation for a short distance with a low noise and low vibration level is in demand. As a response to such a demand, a linear shuttle that applies a linear type elevator in a horizontal direction may be employed.
Referring to FIG. 8, on a chassis 101a of a linear shuttle car 101, instead of using wheels to run the car 101 along a track 105, an air pad 102 is used to float the car 101 above the track 105. When air is blown onto the track 105 from the air pad 102, the car 101 will float and a thin air film is formed between the car 101 and the track 105. The car 101 can then run smoothly in the horizontal direction. The car 101 is moved horizontally by a linear motor having a primary side 103a disposed on the bottom of the chassis 101a, and a secondary side 103b disposed on the track 105.
Referring to FIG. 9, a brake skid 104 (not shown in FIG. 8) is provided on the chassis 101a. When the chassis 101a floats above the track 105, the brake skid 104 also leaves the track 105 and there is no braking action of the brake skid 104. Thus, the car 101 will be able to run. Referring to FIG. 10, on the other hand, when the car 101 is not floating, the brake skid 104 will be in frictional contact with the track 105, and the car 101 is braked (or stopped). Accordingly, with this type of conventional linear type shuttle, the brake skid 104 needs to be separated from the track 105 to allow the car 101 to run. That is, the chassis 101a needs to be floated from the track 105.
Referring to FIGS. 9 and 10, when the brake skid 104 is in contact with the track 105, a gap 60 between the primary side 103a and the secondary side 103b of the linear motor is narrow, e.g., approximately 5 mm. If the car 101 is floated to allow the car 101 to run horizontally, a gap 62 is created between the skid 104 and the track 105, having a distance of, e.g., approximately 14 mm. In that case, the gap 60 increases to approximately 19 mm. However, the ideal gap 60 between the primary side 103a and the secondary side 103b should be as narrow as possible, e.g., approximately 5 mm, to efficiently drive the linear motor. Accordingly, such an increase in the gap 60 reduces motor efficiency.